Conduit tractor



April 17, 1956 c. E. BOUCHER 2,742,259

CONDUIT TRACTOR 2 Sheets-Sheet 2 Filed April 6, 1953 INVENTOR.

CORMACK E. BOUCHER ATTORNEYS United States Patent 2,742,259 CONDUIT TRACTOR Cormack E. Boucher, Seattle, Wash. Application April 6, 1953, SerialNo. 346,889

17 Claims. ((21.254-1345) different diameters and some tractors have insuflicienttractive force to move heavy loads.

It is an object of the present invention to provide a new and improved tractor for use in a cylindrical conduit that is relatively rugged yet relatively light in weight and easily manipulated and inserted into a conduit by a single person.

A further object of the invention is to provide a new 7 and improved conduit tractor which is readily adjusted for use in conduits of great variance in internal diameter.

Another object of the invention is to provide a conduit tractor capable of moving relatively heavy loads through pipe lines and the like.

A more specific object ofthe invention is to provide a new and improved arrangement for insuring a firm gripping engagement of the traction elements of a conduit tractor with the walls of a conduit.

Another object of the invention is to provide means to assist in stopping a tractor in a predetermined position within a conduit. 7

Other objects and advantages of the invention will become more apparent hereinafter.

In accordance with the illustrated embodiments, the tractor of the present invention comprises an elongate frame or housing adapted to be connected at one end to apparatus to be moved through a conduit, said apparatus supporting the connected end of the tractor. A plurality of drive wheels are arranged about the opposite end of the tractor, the drive wheels being mounted on spring biased arms pivoted to thehousing with-means provided whereby each of the arms maybe pivoted simultaneously to effect adjustment of the tractor for accommodation to conduits of different internal diameters. A motor'is provided in the housing and is drivingly connected to each of the wheels for driving the tractor longitudinally of a conduit. A new and improved brake means is also provided on the tractor for stopping the motor whereby the ofa U 2,742,259 Patented Apr. 6

Fig. 4"is an end view of the tractor as viewed in the direction of the arrows 4-4 of Fig. 1;.

Fig; 5 is an enlarged, cross-sectional view along the line 55 of Fig. 4 illustrating the construction of the motor brake; and I Fig. 6 is an enlarged cross-sectional view along line 6-6 of Fig. 1 showing further details of the brake.

Referring now to the drawings, a cylindrical conduit such as a pipe is shown at 10 and within which the tractor of the present invention is shown. The tractor of the invention is shown connected to a portable X-ray unit 12 such as is used in radiographic inspection ofannular sections of the pipe such as the annular weld 13., The X-ray unit in this instance is shown as comprising a metal housing having an X-ray tube (not shown) mounted coaxially within the central section. The X-ray tube is arranged to emit radiation throughout an angle of 360 degrees about the longitudinal axis of the unit to form a shadow picture of the weld 13 on a film mounted within a suitable holder 19 and wrapped around the outside of the pipe 10 over the weld. Further details of the internal construction of the X-ray unit are not shown or described herein since such details are not essential to the present invention, and reference is made to my Patent No. 2,547,996, issued April 10, 1951, for further information regarding X-ray units for weld inspection. The X-ray unit 12 is equipped with supporting wheel assemblies at each of its opposite ends comprising a plurality of wheels 22 mounted on the ends of resilient bracket arms 23. The wheel assem-' there will be an inherent tendency for the X-ray unit,

as well as the propelling tractor, to rotate to a greater or lesser degree about the axis of the pipe and the supporting wheels should be so spaced about the housing that the unit, or at least the X-ray tube therein, will be maintained in the predetermined aligned relation, with respect to the pipe axis irrespective of rotational movement of the X-ray unit about the pipe axis. As shown in Fig. 1, the end wall of the X-ray unit adjacent the tractor is provided with an outwardly extending cylindrical flange 27 adapted for receiving a ring 28. The ring 28 is provided with a plurality of bracket arms 29 joined together at a coupling fixture 30 adapted to be cooperatively connected to the conduit tractor through a universal coupling to be hereinafter-described. The coupling fixture 30 is aligned with the longitudinal axis of the X-ray unit and is adapted to support one 'end of the tractor in coaxial alignment with the cylindrical pipe 10.

motor 31 is coupled at one end directly to the X-ray unit 12 as will be more fully explained hereinafter, the opposite end of the motor 31 being secured by suitable means to the coaxial gear unit 32. Arranged about the gear unit 32 are a plurality of traction elements shown in the drawings as being three in number and in this instance consisting of three rubber-treaded wheels 35. It will be understood that while a greater number of wheels may be provided, a minimumof three is necessary to properly support the tractor within a conduit. The wheels 35 are spaced substantially uniformly augularly apart the, opposite. end of. each of. the, arms being pivotally mounted n.tl1e, gear housing portion 32. medially of the tractor with the arms extending angularly outwardly frorn thetractor.axistowardsthe end of the tractor oppositethe V riiotor 31. The. arms, are di vided'. longitudinally into twosiniilar complementary parts 38,39, shaped toprovideyokesfl inlthe opposite ends thereof aszbest shown in Fig. 3, andgboltedtogether as indicated in Fig, l. The

armends mounted. on the-gear housing portion 32 are,

suitably. journaled thereon as will be described more fully hereinafter, the pivotal axis of each of the arms lying in a plane atright angles to the longitudinal axis of the. tractor'whereby the. arrns will pivot in planes parallel toancl intersecting the-longitudinal axis of the tractor. It will be evident thatthepivotal planes of the.

arms are spaced uniformlyangularly apart about the longitudinal axis of the tractor.- The wheels 35 are rotatably supported in the. yoke: on the free end of the corresponding arm, the wheels, being fixed to'a shaft 43 journaled at its opposite end in the arm parts. 38, 39,

respondingly. It will be seen that, by moving the collar longitudinally of the tractor the arms 36 will pivot correspondingly toward or away from the tractor axis.

Stop means are provided for the collar and further means are provided for resiliently biasing the arms into pressurable engagement with the inner walls of the conduit. Referring now moreparticularly to Fig. 2, a split sleeve 59 is mounted on the tubular extension 33 be- Also fixed to each of the wh'eel.shafts..43 is wheel drive sprocket ,45;

Meansareprovidedfor eifectinga driving connection between the motor. means 31 and the wheels Mounted in the gear housing 32v and driven by; the motor through any suitable speed reduction arrangement (not:

shown) is aspiral gear,101;which drives a'complementary spiral gear 102 fixed to a; shaft 103- which extends at right angles to the; axis of'the tractor. The. ends'of the shaft 103. are journaled in suitable. brackets on the outer portion of the gearhousing32, the bracketscomprising a. portion, 104 integral with the gear housing 32,- and .a portion: 105 bolted to. the. portion 104. Suitable bearings 107 and 109 are provided .to-suppor-t the shaft 1 03'in the brackets 104,105. An annular grease seal 1084s provided betweenthe shaft 103and the bracket portion 104; Also-keyed. to. the shaft 103 is asprocket "110.;Which is. connected to drivethe drive wheel sprocket 45.by suitable means such as the roller sprocket chainv 1 11. Obviously other drive. arrangements may be utilized audit will be. appreciatedv that it is not necessary that each or the wheels35: be drivenby the motor, 'but it is preferred that each be driven-to assure sufficient tractive force. a a

The bracket. portions 104,- 105 are formed with outwardly extending coaxial-bosses 114; 115- respectively upon. which arerjournaled the arms 36, suitable bushings. 116, 117 being provided betweenzthe bosses andthe arms.'

Means are. provided-forsimultaneously adjusting the angle of inclination of each of the. arms so that the wheels 35 may be simultaneouslymoved toward or away from the'tractor axis whereby the tractor may be readily adapted for use in conduitsof dilferent internal diameter.

As shown inFigs; l and 2, a collar 49 is mountedion' the tubular extension 33 spaced forwardly of the arms 36 in the direction of their inclination, which collar isslidable longitudinally of'the tubular extension. Extending between thecollar49 and the free end of each of the arms 36 is a pair of struts 50. The struts 50 ,are pivot which 'may be adjusted as to length, having-a central portion in-the opposite ends-of which are 'threadably receiveclthe screwend-portions 56; 57, respectively, 0 threaded 'in opposite directions whereby turning of'the central portion 55 will -lengthen or shorten the strut cortween the collar 49;and the left end of'the tractor as it is shown, which sleeve is adapted to be moved longitudinally of the extensi0n33: Means are provided for clamping the: sleeve 59. in. positiomwwhich. means comprises a screw 60 extending through cars 61. The end of the sleeve 59' adjacent the collar'49 is-provided with an outstanding radial flange 64. Arranged about the tube 33 and abutting 'at one end against the flange 64 is a helical spring 65, the collar 49 enclosing the spring and having an inwardly turned fiange 66. at its. right end against which the opposite end of thespring 65abuts. In placing the tractor of the. invention within. a conduit, the positionof thesleeve59is first adjustedon thetube 33 withthecollar 49 in contact with the spring 65 but with the spring uncompressed so that the wheels 35 define afully bias the wheels against the inner surface of the.

conduit. Itwill be seen that the tractor may be easily adjusted. for-use in. conduitsofvarious sizesby the simpleexpedientof moving theqsleeve 59' longitudinally of they tractor toa suitableuposition. Furthermore, because-of the relatively great permissible biased movement of'the arms, the tractor is'adapted to travel through conduits having;relatively greatsurfaceirregularities such as occar in; the sharp. bends of expansion loops of pipe lines"- and: whichbends the tractor of the invention easily negotiates. Moreover, the simplicity of-the construction of the tractor and of the component'parts results in a tractor relatively light in weightso that it may be readily handled by one-man for insertion in aconduit, yet the tractoris rugged and has-sufficient tractive force tomove relatively heavy loads through aconduit. The principal load, in thecasc. of apparatus as. shown, consists-ofthe power. supply cable 70, which maybe a. mile. on-so in:

length.

' Powermaybe supplied tothe'tractor motor'through a conductor cable and throughwhich cablethe operation of the. motor'may also becontrolled; The cablemay be anchored in any suitable manner within .the tube: 33 of the tractor. The powerfor the'X-ray unit'rnay'also. be supplied through the cable .70, an interconnecting cable;

71 being. shown; between the: X-ray unit and the: tractor.

'In' certain operationsitis necessary that the position ofthevtractor 'or; the unit which it ispropellingbeposi= tioned. rather, exactly within the conduit. For example,- in-malging radiograph's of pipe-welds, it is important that the X-fray tube be positioned: in predetermined'relation with respect to the pipe=weld.. A. convenient way of ac curately, locating. .welds in a. conduit is described and signalis transmitted to the-operator. The-tractor is preferably, providedwith a constant speed motor, sothat the" operator can. stop thetractor-a predetermined period of time after receipt of the signal, correspondingtothe time necessary for thetractor to. propel theunit to a position-- where the X-ray tube will be alignedwith the weld. Automatic means may be provided, of course, for stopping the.

I I motorafter a predetermined interval of time to accomplish m n case, itis necessar-y that the 73 having a planar, end surface.

. power thereto is cut off is provided in "the present, invention and will .now be described'with particular reference to Figs. and 6. Theend of the motor housing portion -31 to which the X-ray unit is connected is formed with a tubular projection '74 coaxialwith the motor shaft 75, which shaft .extends a short distance into the housing projection 74 and is provided with an enlarged end portion Formed on the inner surface of the projecting housing portion 74 and extending longitudinally thereof are a plurality of ribs 77 adapted to guide the longitudinal movement of a friction member comprising a disc 79 of steel or other magnetically attracted material having a plurality of recesses in the periphery thereof in which are received the ribs 77.

Secured to the side of 'the disc :79 adjacent the end of the motor shaft is a disc or sheet 81 of fibrous material having ahigh co-efficient of friction adapted to engage the shaft end portion 73 to stop the motor rotor. Resilient means are provided to bias the friction member against the motor shaft to stop the motor, and electromagnetic means are provided to neutralize the biasing effect of the resilient means when it is desired that the motor operate. Mounted Within the housing projection 74 is the winding 82 of an electromagnet, in the axial opening of which winding is arranged a soft ironcore meniber83. The end of the core member 83 adjacent the steel disc 79 is provided with an outwardly extending radial flange 84, a-compression spring 85 being arranged between the flange and the winding 82 to bias the core member into contact with the disc 79 and to urge the friction disc 81 against the end of the motor shaft.

7 Themagnet winding 82is provided-with an outwardly extendingflange -87 on the end thereof adjacent the motor, which flange is. adapted to .abut against the ends of the ribs 77; Threaded in the outer end of the housing projection 74 is a cap 88 which abuts against the magnet winding 82 whereby the winding is held .in place between the cap and the ribs 77. The magnet winding is connected through suitable leads indicated at 89 and in a suitable manner to the circuit of the motor so that, when the circuit to the motorvis opened to stop the motor, the magnet winding 82 is deenerg'ized whereby the spring 85 will immediately bias the friction member 79, 81 ,into contact with the motor .shaft to brake the motor. The

magnet winding is adapted, on the other hand, to be energized when power is supplied to the motor so that the core member 83 will be drawn inwardly of the winding, attracting and carrying therewith the friction member 79, 81 to relieve immediately the braking force on the motor whereby the rotor will be free to rotate. Since I the brake will immediately stop the motor, the tractor and the X-ray unit will not'creep after the power is shut off and theitractor and X-ray unit may be accurately positionedwi'thin-a conduit.

Because of the tendency of the tractor to shift rotationally about the conduit axis, couplingshould be made to theX-rayunitor othertapparatus connectedthereto along the line of the conduit axis so that suchrotational movements will not interfere with the functioning of such other apparatus. .As shown in- Fig. 6, a split coupling'collar 91=is secured about the housing projection 74 by means of bolts 92 or other suitable means, to which collar is welded in axial alignment with the longitudinal axis of the housing an eye member 93 comprising a portion of a universalicoupling indicated at 94 through which the connection is made to the X-ray unit coupling fixture 30.

which maybe desirable where large tractive force with .the conduit is desired On-the otherhand asimple supporting wheelassembly'such as that utilized on the X-ray unit .12 may be provided to support the motor housing por- .tion of .the tractor where the additional traction is not necessary. In any case such adaptations may be made by those skilledin the art following the present specifi- .mentof the present invention, it should be apparent to those skilled in the art that the same permits of modification jin arrangement and. detail. ,I claim as my invention all such modifications as come within the true spirit and scope of the following claims.

I claim:

'1. In a conduit tractor, a motor including a housing, an arm pivotally mounted at one end thereof on said housing for relative pivotal movement toward and away therefrom, a traction element operatively mounted on the other end of said arm adapted to engage the wall of a conduit to propel the tractor longitudinally thereof, and drive means operatively connecting said motor to said traction element and operative in any position of said am relative to. said housing to transmit power. to said traction element forldriving thesame,

2. In a conduit tractor, a .motor including a housing,

an arm pivotally'mounted at one end thereof on said housing for relative pivotal movement toward and away therefrom, a drive wheeladapted to engage the wall of a conduit to propel the tractor longitudinally thereof mounted on the other end of said arm, and drive means In the present instance, the tractor has been illustrated as being partially supported by theapparatus to which it is connected. Obviously the tractor may be a self-supported unit and provided with additional drive wheels in the manner shown to support the opposite end of the housing operatively connectingsaid motor to said drive wheel and operative in any position of said arm relative to said "housing'to transmit power to said drive wheel for driving the same. p r

3. In an elongate conduit tractor, means for supporting said tractor in a conduit with the longitudinal axis thereof coincident with the longitudinal axis of said conduit, said means including an armpivotally mounted at one end thereof on said tractor for relative pivotal movement toward and away from said longitudinal axis thereof, a drive wheel adapted to engage the innner surface of a conduit to drive the tractor longitudinally thereof, said drive wheel being mounted on the other end of said arm,

prime mover means .operativelyconnecte'd to said drive wheel and operative in any position of said arm relative to said longitudinal axis to transmit power to said drive wheel for driving the same, and means for adjusting the angular position of said arm relative to said tractor longitudinal axis. a

4-. In a conduit tractor includinga housing, an arm pivotally mounted at one end thereof on said housing for relative pivotalmovement toward and away from said housing, a drive wheel adapted to engage the wall of a conduit to drive the tractor longitudinally thereof, means mounting'said drive wheelon the other end of said arm, a motor means operatively connected to said drive wheel to supply power thereto in any position of said arm, relative to said housing-for driving said drive' wheel, and adjusting means connected to said housing and said arm for. adjusting the position of said arm relative to said housing, said adjusting means including a resilient ele- 6. An elongateconduit tractor 'having at" least three drive wheels spaced substantially equally angularly about the. longitudinal axis of said tractor, resilient support means ,inounting at'leastone of saidwheels on said tractor for movement toward and away from said tractor'for tively connected to supply power to all of said wheels including said one wheel in any position thereof relative to said'tractor for drivingsaid wheels.

7. In aconduit tractor, thecombination of an elongated housing, at least three drive wheels mounted on said housing in substantially uniformly angularly spaced apart relation about the longitudinal axis of said housing, adjustable means supporting said wheels for relative movement toward and away from said longitudinal axis, motor means in said housing, and drive means operatively connecting said motor means to each of said wheels to supply power thereto in any position of .said wheels relative to said axis for driving said wheels.

8. A conduit tractor comprising an elongate housing, at least three drive wheels spaced equally angularly about said housing at substantially equal distances from the longitudinal axis thereof, adjustable interconnected support means mounting each of said wheels on said housing for simultaneous equal movement of each of said wheels 'toward and away from said axis, motor means in said housing, and drive means operatively connecting said motor means to each of said drive wheels to supply power to said wheels in any position thereof relative to said axis for driving said wheels. 1

' 9. In a conduit tractor, the combination comprising an elongated housing, a plurality of at least three supporting wheels mounted on said housing for supporting the'same in a conduit, supporting arms for said wheels, said supporting arms being pivotally mounted at one of their ends on said housing, said wheels being rotatably mounted on the other ends of said arms, and motor means in said housing and connected to at least one of said wheels to supply power thereto in any position of the arm upon which said one wheel is mounted for driving said one Wheel.

10. A conduit tractor comprising a motor including a housing having a longitudinal axis, at least three drive wheel supporting arms pivotally mounted on said housing, the pivotal axis of said arms lying in'substantially the same plane normal to the longitudinal axis of said housing, whereby said arms pivot in radial planes, said arms being spaced substantially uniformly angularly apart about said longitudinal axis and extending angularly therefrom, a drive wheel rotatably mounted on the free end of each of said arms to rotate in the radial plane a 11. A tractortfor use in a cylindrical conduit, said tractor comprising an elongated frame, at least three drive wheels mounted on said frame for engaging thewall of said conduit and supporting said tractor in said conduit with the longitudinal axis of said frame substantially coinciding with the axis of said conduit, an arm for supporting each of said wheels, said arms being pivotally mounted at one end thereof on said frame for pivotal movement of the opposite end thereof relatively toward and away from said frame, said wheels being mounted on the opposite end of the corresponding-arm to rotate in the direction of the longitudinal aXisOf said frame, prime mover means operatively connected to each of said wheels to supply power thereto in any position of said arms relative to said frame for'driving said wheels, and resilient means on said frame operatively connected to said arms for resiliently biasing each of said arms into firm engagement withthe wall ofa conduit.

y} 12 A tractor for use, in' a cylindrical conduit, said tractor comprising anelongatedlframe, at least three drive wheels mounted on said frame for supportingthe same in a conduit coaxially therewith, a supporting arm for each of said wheels pivotally mounted at one end thereof on said frame and extending angularly outwardly from said frame, the pivotal axis of each of said arms lying in substantially the same plane normal to thelongitudinal frame axis whereby said arms pivot in planes parallel to and intersecting said frame axis, said arms being spaced substantially equally angularly circumferentially of said frame, said wheels being mounted on the opposite end of the corresponding arm to rotate in the plane of movement thereof, said tractor including motor means operatively connected to each of said wheels tosupply power thereto in any position of said arms relative to said frame for driving said wheels, and means on said frame operatively connected to said arms for eifecting equal pivotal movement of each of said arms about its pivotal axis in response to pivotal movement of one of said arms.

13. A tractor for use in a cylindrical conduit, said tractor comprising an elongated frame, at least three drive wheels mounted on said frame for supporting the same in a conduit with the longitudinal axis of the frame coincident to the axis of the conduit, an arm for supporting each of said wheels, said arms being pivotallymounted at one end thereof on said frame and extending angularly outwardly from said frame, the pivotal axis of each of said arms lying in substantially the same plane normal to said frame axis whereby said arms move in planes parallel to and intersecting said frame axis, said wheels being mounted on the opposite end of the corresponding arm to rotate, in the plane of movement thereof and adapted to engage the wall of a conduit, motor means operatively connected to each of said wheels to supply' power thereto in any position of said arms relative to said frame for driving said wheels, and adjustable means on said frame operatively connected to said arms for biasing each of said arms outwardly of said frame and for effecting equal pivotal movement of each of said arms about its pivotal axis in response to pivotal movement of one of said arms.

14. A conduit tractor comprising an elongated tubular frame, at least three substantially identical wheel supporting arms pivotally mounted medially of said frame and extending angularly therefrom toward one end of said frame, the pivotal axis of each of said arms lying in substantially the same plane normal'to the longitudinal axis of said frame, the pivotal planes of said arms being spaced substantially uniformly angularly apart, a tractor drive arms, and resilient means mounted on said frame to resist movement of said collar toward said one end.

15. A conduit tractor comprising an elongated generally tubular frame, at least three wheelrsupporting arms of substantially equal lengthpiyotally mounted medially of said frame'and extending angularly therefrom toward one end of said frame, the pivotal axes of said arms lying in a plane normal to the longitudinal axis of said frame, the pivotal planes of said arms being spaced substantially uniformly angularly apart about said axis, a tractor drive wheel mounted onthe free end of each of said arms to rotate in the planeof the corresponding arm, a collar slidably mounted on said frame, a strut connecting the free end of eachrof said arms with said collar whereby movement of said collarlongitudinally of said frame will effect equal pivotal movement: of said arms, adjustable stop means on said frame adjacent said one end with said arms spaced substantially uniformly apart about a .the longitudinal axis of said frame and with each of said arms pivoting in 'a plane parallel to and intersecting said longitudinal axis, said wheels being rotatably mounted one on each of the opposite ends of said arms to rotate about an axis normal to the plane of movement of the corv 10 housing for supporting said housing coaxially in said conduit and for driving said tractor longitudinally of the conduit, a drive wheel supporting arm for each of said drive wheels pivotally mounted on saidlhousing medially thereof and extending angularly outwardly therefrom toward the end thereof opposite said coupling means,

said arms being of substantially equal length and spaced substantially equally angularly apart, the pivotal axis 'of 9 each of said arinslying in a plane atright angles to the longitudinal axis of said housing, said drive wheels being mounted on the free end of the corresponding arm for rotation in a plane parallel to and intersecting the' axis of said conduit, a collar mounted on said housing adjacent responding arm, a collar mounted on said frame for move- 7 ment longitudinally thereof, astrut extending between the said opposite end of each ofsaid arms and said collar, said struts being pivotally secured at one end thereof to the corresponding arm and at the other end thereof to said collar whereby movement of said collar longitudinally of said frame will correspondingly pivot said arms toward or away from said frame, and means for adjusting the longitudinal position of said collar. on said a frame. t a r V t 17. A motive tractor for a unit disposed within 'a cylindrical conduit having tractor coupling means coincident with the axis of said conduit and adapted to be connected to said tractor and to support one end of the same, said tractor including an ,elongated, generally tubular motor "and gear housing, means on one end of said housingcoaxial therewith forcoupling theisame to said unit, at least three drive wheels mounted on said 443,824 Cope Dec. 30, 1890 621,018 Benjamin Mar. 14, 1899 632,353 7 Kohler Sept. 5, 1899 774,525 ,Mack Nov. 8, 1904"- 1,810,143 Okey L June 16,1931 2,455,273 Schott et ali Nov, 30, 1948 2,514,694 Chapman July 11, 1950 said opposite end and movable longitudinally of said housing, strut means connected between each of said arms and said collar for'holding each said arm outwardly of said housing, stop means on said housing for limiting movement of said collar toward said opposite end, spring.

means operatively connected between said collar and said stop whereby said arms may be pivoted inwardly of said housing against the bias of said spring means, and motor means in said housing drivingly connected to each of said drive wheels.

References Cited in the file of this patent UNITED STATES PATENTS Boucher ;July 22, 1952 I 

